python singleton

最新推荐文章于 2025-09-06 09:26:50 发布

转载最新推荐文章于 2025-09-06 09:26:50 发布 · 62 阅读

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原文链接：http://www.cnblogs.com/otfsenter/p/6364864.html

文章标签：

#python

本文介绍了一种使用装饰器实现单例模式的方法，并通过一个简单的Python类示例展示了如何确保类实例的唯一性。该装饰器可以方便地应用于任何希望采用单例模式的类。

coding:utf-8

class _SingletonWrapper:
"""
A singleton wrapper class. Its instances would be created
for each decorated class.
"""

def __init__(self, cls):
    self.__wrapped__ = cls
    self._instance = None

def __call__(self, *args, **kwargs):
    """Returns a single instance of decorated class"""
    if self._instance is None:
        self._instance = self.__wrapped__(*args, **kwargs)
    return self._instance

def singleton(cls):
"""
A singleton decorator. Returns a wrapper objects. A call on that object
returns a single instance object of decorated class. Use the wrapped
attribute to access decorated class directly in unit tests
"""
return _SingletonWrapper(cls)

@singleton
class Singleton:
def init(self):
self.state = 'a'

p1 = Singleton()
p2 = Singleton()
p3 = Singleton()

print p1==p3

转载于:https://www.cnblogs.com/otfsenter/p/6364864.html